I can't promise that lone mite will come out with the next shed- it might hang on well enough that the shed will just come off around it & on it will stay. Plus it will be bigger & stronger by then.
You need to be very careful around their eyes...sometimes an experienced herp vet would be a better choice. I actually wouldn't use mineral oil, as various oils seem to mess up their future sheds, & their eye-caps are the last area that you want to shed poorly. Their eyes are protected by the "spectacle"- so if that was my snake, I think I'd dab a bit of Dawn dish soap* from a Q-tip onto the mite, as that should smother him (without the issue that oils have) & maybe he'll lose his grip then. (*diluted or not) Can't say how long it might take though- it has literally been over 20 years since I've had a snake with mites, & I don't miss them one bit. It if stays alive, it might do more damage by the time he has his next shed...ick, I hate mites! Poor baby snake...let us know how it goes?
I'm sure you're aware that mites can also hide under their scales, or leave their eggs behind & cause another wave of the little monsters? So as far as treatment, it's often not "once & done".
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